Neem oil ( Azadirachta indica A. Juss) affects the ultrastructure of the midgut muscle of Ceraeochrysa claveri (Navás, 1911) (Neuroptera: Chrysopidae)

Abstract

Cytomorphological changes, by means of ultrastructural analyses, have been used to determine the effects of the biopesticide neem oil on the muscle fibers of the midgut of the predator Ceraeochrysa claveri. Insects, throughout the larval period, were fed eggs of Diatraea saccharalis treated with neem oil at a concentration of 0.5%, 1% or 2%. In the adult stage, the midgut was collected from female insects at two stages of adulthood (newly emerged and at the start of oviposition) and processed for ultrastructural analyses. In the newly emerged insects obtained from neem oil treatments, muscle fibers showed a reduction of myofilaments as well as swollen mitochondria and an accumulation of membranous structures. Muscular fibers responded to those cellular injuries with the initiation of detoxification mechanisms, in which acid phosphatase activity was observed in large vesicles located at the periphery of the muscle fiber. At the start of oviposition in the neem oil treated insects, muscle fibers exhibited signs of degeneration, containing vacant areas in which contractile myofilaments were reduced or completely absent, and an accumulation of myelin structures, a dilatation of cisternae of sarcoplasmic reticulum, and mitochondrial swelling and cristolysis were observed. Enzymatic activity for acid phosphatase was present in large vesicles, indicating that mechanisms of lytic activity during the cell injury were utilized but insufficient for recovery from all the cellular damage. The results indicate that the visceral muscle layer is also the target of action of neem oil, and the cytotoxic effects observed may compromise the function of that organ.

Sublethal Effects of Solanum nigrum Fruit Extract and Its Pure Glycoalkaloids on the Physiology of Tenebrio molitor (Mealworm)

“…A similar phenomenon was observed in the case of exposure to other toxic substances, such as boric acid [35] and tomato or potato leaf extract [36]. Although the intensity of the ultrastructural malformations differed between the tested organs, species, and substances, some of those effects were similar: swollen nuclear envelopes and endoplasmic reticulum, cytoplasmic vacuolization, or swollen mitochondria have been reported for many toxic substances, including synthetic pesticides [16,37] or plant-derived substances [15,29,38,39]. These ultrastructural changes may be due to the increased production of reactive oxygen species, which has been reported for various toxic substances [35,40,41,42].…”

Efficacy of Natural Extract from Ocimum Species against Fungus Gnats Infesting Plant Saplings

“…Such an instantaneous effect is possible when the extract is either highly toxic or can strongly stimulate the insects olfactory system. 7,10,11 Ocimum extract is highly water soluble, relatively less oily and is extensively used by humans as an immune booster, hence it being a potent insecticidal is less likely. However Ocimum extract is highly aromatic.…”

“…[6][7][8][9] Among the natural product based pesticide, neem oil is shown to be very effective and safe to use. 10,11 The mechanisms of action of neem based products include 1) suffocating the insect by forming a layer of coating on the insect's body, 2) repelling the insects by stimulating their olfactory receptors, 3) disrupting the moulting/growth/development of the insect/ larvae and 4) direct insecticidal/larvicidal effect. Among these mechanisms of actions, the feasibility to repel insects by stimulating their olfactory receptors is of specific interest, as this is humane and least disruptive to the ecological balance.…”

“…Among these mechanisms of actions, the feasibility to repel insects by stimulating their olfactory receptors is of specific interest, as this is humane and least disruptive to the ecological balance. 7,10,11 Similar to the neem, other aromatic plants may also be helpful in repelling the insects. Hence in this study we tested the efficacy of natural extract from Ocimum species in repelling the fungus gnats infesting plant saplings.…”

Larvicidal Action of Cannabidiol Oil and Neem Oil against Three Stored Product Insect Pests: Effect on Survival Time and in Progeny

“…Additionally, much scientific research has been conducted on the neem tree [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. The extracted oil shows pharmaceutical, anticancer, antioxidant and other properties according to many recent studies [ 27 , 28 , 29 , 30 , 31 , 32 ].…”